The present invention relates to improvements in interaxle transmissions for motor vehicles wherein the operators can select for use either two-wheel or four-wheel drives.
It is known to provide inter-axle transmissions which are constructed and arranged so that the operator of a vehicle having front and rear wheels can selectively use either a rear wheel drive or a front and rear wheel drive. It is also known to provide inter-axle transmissions wherein the ratio of torque transmitted to the front and rear wheel drives can be preset at a desired ratio and wherein desired limited slippage between the front and rear wheel drives can occur, as is disclosed, for example, in the U.S. Pat. No. 3,577,803, granted May 4, 1971, to Mueller. There is a need for an improved inter-axle transmission incorporating either or both of the foregoing concepts, and wherein the transmission can be shifted between its rear wheel drive position and its front and rear wheel drive position in a more effective manner than was heretofore possible with prior art structures. There is also a need to incorporate in such an improved transmission features that are taught in U.S. Pat. Nos. 3,393,582 and 3,393,583, granted July 23, 1968, and No. 3,831,461, granted Aug. 27, 1974, to Mueller.